A. Field of the Invention
The present invention relates to fluid dispensing containers, and in particular, to containers useful for dispensing multiple dosages of fluids where the interior of the container is maintained in a sterile condition even when the fluid is preservative-free.
B. Problems in the Art
A variety of different ways exist to dispense fluids. A simple squeeze-bottle is a convenient and economical fluid dispenser. However, it is has disadvantages and even deficiencies in some situations.
For example, if the fluid to be dispensed contains ingredients which must be kept in a sterilized condition, an ordinary squeeze bottle presents the risk of contaminants entering through the outlet opening. Additionally, it presents the risk that air replacing dispensed fluid will contaminate the contents.
One approach to overcoming this problem is to add preservatives to the fluid to attempt to maintain the sterile conditions inside the container. Such things as germicidal agents are used in these preservatives A disadvantage of this approach is that the preservatives can contain substances which can detrimentally effect the use of the fluid. For example, fluids used in eye care and which contain germicidal agents can be irritating and even somewhat toxic to the user's eyes.
Two attempts to provide dispensing systems for fluids without utilizing preservatives are form, fill, and seal packaging, and aerosol containers. While these eliminate use of preservative substances, they also have problems and deficiencies.
The major problem with form, fill, and seal packaging, such as is known in the art, concerns what is called "suck back" with respect to the container. When fluid is being dispensed, pressure is exerted on the exterior of the container. When pressure is released, the negative pressure in the container pulls back whatever fluid is left in the outlet from the container. The risk is that microbial contamination, through airborne particles or direct contact with the fluid, will be pulled back into the container and destroy its sterility.
Aerosol containers are expensive and are difficult to control, especially when small quantities of material need to be dispensed. Additionally, the inherent structure of aerosol containers is prone to leakage of the propellant which can affect sterility and operation of the container. This is significant also with respect to limiting the shelf life of the fluid. Also, it is significant with respect to environmental concerns regarding leakage of propellants into the atmosphere.
There are a number of containers for dispensing fluids which are not aerosol containers or form, fill, and seal packaging containers. Examples of some of these containers can be found at:
U.S. Pat. No. 1,752,085 (Hinkle); PA1 U.S. Pat. No. 2,812,117 (Butkus, et al.); PA1 U.S. Pat. No. 3,952,902 (Prouty, et al.); PA1 U.S. Pat. No. 4,159,790 (Bailey); PA1 U.S. Pat. No. 4,259,954 (Scott); PA1 U.S. Pat. No. 4,340,157 (Darner); PA1 U.S. Pat. No. 4,533,068 (Meierhoefer).
While some of the above patents disclose fluid dispensing containers which do not have the above mentioned problems, there is still a need in the art for a container to dispense preservative-free fluids controllably, efficiently, and economically, and to store and maintain the fluids in a sterile condition.
Many of the above patents utilize ball valves or some type of a duckbill one-way valve. Some utilize these valves to prevent suck-back or to allow the entry or exit of air from the container. However, these type of valves are not sufficient to adequately insure maintenance of sterility of the inside and contents of the container, or to acceptably reduce the suck-back problem.
It is therefore a principal object of the present invention to provide a container for dispensing preservative-free preparations which solves or improves over the problems and deficiencies in the art.
A further object of the present invention is to provide a container as above described which maintains the sterility of the fluid within the container, both during storage and dispensing.
Another object of the present invention is to provide a container as above described which does not allow suck-back of fluid into the container after dispensing fluid from the container.
Another object of the present invention is to provide a container as above described which allows multiple dosages of variable quantities of the fluid to be dispensed.
A further object of the present invention is to provide a container as above described which seals the container from leakage and outside contaminants before and after dispensing of fluid.
A still further object of the present invention is to provide a container as above described which allows sterilized air to replace fluid dispensed from the container.
Another object of the present invention is to provide a container as above described which is easily sterilized before filling with fluid.
Another object of the present invention is to provide a container as above described which is easy to control so that precise amounts of fluid can be dispensed to a targeted area.
Another object of the present invention is to provide a container as above described which is economical, efficient, and durable.
These and other objects, features, and advantages of the present invention will become more apparent with reference to the accompanying specification and claims.